Telephone system



April 25, 1933- E. E. HINRICHSEN 1,905,711

jIELEPHONE SYSTEM Filed March 18, 1951 INVENTOR EE. H/NR/CHSE N ATTORNEY {EDWARD E; HINnroHsEN, or nnwyoitkfit.

' busy or that the subscriber does not answer: There the line is busyza'second call after a uncompleted calls.

Patented Apr. 25, 1933 p r I Y, nssienon ro BELL TELEEHONEBABO- 1? RA'ronIn-s, IncoRroRA'rE-n, ornsw years; n. Y.,AI C,RPOR-ATIO1\T onnnwYoRK j r-E EPiione system Application file 1 March 18,1331! Serial No 523,388.

This invention relatesito telephone systems and has for its object to in creasethe efficiency of such systems by reduclng the number of The two'chiefflreasons for failure to com; plete connections are'that the lineiis already short interval will usually becompleted.

here the call is not answeredit may re? quire many trials ceivedy? I a i In accordance with the present invention s'ubscriberswlio receive many incoming calls, but who are cofvnecessity away from their before a response is re telephones at intervals such:asphysiCianS v etc; may secure special serviceby which .in-

- coming calls which are-not answered within a predetermined length: of time will be answered by an operator who will record the identity of the calling party and any. mes+ sage which he may care to'givefi interval may convenientlybe measured by the intermittentapplication'of ringing current to the subscribers line andmay be varied in length to suit the requirements of partieu lar subscribers. This service may be controlled by a-keyat the operators position so that itmay be effective only during certain hours orrat the requestzof the subscriber. If a call-is received duringthe time that the service is efi'ective thesubsequent removal'of the receiver at the subscriberssubstation will immediately connect the subscriber-with the operator so thatshe may deliver the mes-1 sage received. a 1 i5 A somewhat similar arrangement; .by which the service is given to all subscribers; is disclosed and claimed in United States. application of F. S. Irvine, Serial No. 523,392, filed'March 18, 1931. v

The drawing which illustrates one em:-

bodiment of the inventionwshows acalling 'subscribers line extended bymeansnfa lower contact of cam The time multiple wiring of theline.

the subscriber at substation 105Yisto receive this service, atthe' same time-that "ringing" providing the dont be extended by means of automatic uequipandyfollowing the operation of dial l0 2 ,will

ment not shown) to an incoming selector 103 v and a final selector 104, such as shown in United States Patent 1,658,829, "g'rantedto GHH; Berry February 14, 1928, and through them to the terminals of the wanted'linfe;

The incoming; selector sequence switch :will

thereupon-beadvanced to position 12 in which 7 a ringing circuit is established from ringing source 112 over the/left contact of cam subscribers line, through the substation ringer 107 ,back' over the tip brushes of the final selector 104and incoming selector 103',

106 to ground; Ringing current is applied over this circuit for an sequence switch is advanced to position l 1 l where interrupter 113 is included in thering-i ingycircuit and the subscribers bellis rung. at measuredintervals.

Subscribers, who wish 'the'serviceof having calls incoming during their absence answered. and recorded by an operator, willwbe provided with-equipment such as shown at appear in theline finderand final" selector frames; A convenient method of so'doing-is by means of a cross-connecting rack such as raclr 14A so-tha-t the service maybe'furnished ordiscontinued without interfering with the Assuming that current is applied to his belllO'Z', it is plied over a parallel circuit which traced-from the ringsideiof the line over rack 144, through condenser 115,1 winding of re lay :114, over rack 14% to thetip side of the line.- Therefore each'time'that ringing current is applied the subscribers'line, relay 114 is operated. f I

also ap 1 Key 116 i'sprovided so servicemay be given only at such times as desired by the subscriber. With the key normal," as shown;

may be t ioo 7a interval during which .theincoming selector theoperation of relay 114 in response to the first application of ringing current closes a circuit from ground at key 116 over the con tact of relay 114, brush 121 of the timing 1 switch 120 in its normal position, lower winding of relay 117 to battery. Belay 117 locks in a circuit from ground through itsrupper winding and inner upper front contact back contact of relay 134, to battery connected to the sleeve'terminals of the called subscribers line by the final selector. It also closes a circuit from battery through resistance 139, out er upper front contact of relay 117, to the sleeve terminals 145 of the called line in the 7 line finder frames and to the winding of cutoff relay 140 which functions to disconnect the line relay 141 from the tip and ring of the line. Relay 117', in addition, connects ground over its outer lower front contact, normal contact of brush 122, back contact and winding-of magnet 123 to battery. Magnet 123 operates, opening'its own contact and. ad-

vancing the timing switch 120 to its second position. In this position a circuit is closed from battery through the winding of magelapse before calls are directed to the atten tion of the operator; For instance. some sub scribers may have their telephones at their elbowsland if theydo not answer after the bell has rung once ortwice it is almost certain that they will not answer at all, while other subscribers, who move about more, may still answer after the bell has been rung a large number of times. People, who call such subscribers frequently, may know these habits or may learn .them'from previous experience and will be likely to hold the connection in proportion to the time they expect to wait for an answer. It is, therefore, advisable both from the standpoint of the subscriber and from the standpoint of the telephone company in reducing the number of unco1npleted' calls to vary the time interval measured by switch 120 according to the, wishes and habits of the subscribers. The terminal bank of brush 122 has therefore been wired with-two groups of strapped contacts and two simple switches 142 and 143 are provided. With switch 142 closed the ground connected by relay 117 to the first terminal of brush 122 is also connected to the nextfour terminals and switch'120 is rapidly advanced to position 6. The release of relay 114 after the first rings ing impulse in this case advances switch120 position 7finstead of to position 3; If switch 142 is not closed the advance of switch 120: from position 3 is under the control of;

relay 114 and switch 120 reaches position 7 only after five application's of'ringing current. When switch 142 .is open, switch v143 is usually closed to provide a circuit for restoring the timing switch'to normal if the ringing current is removed before the timing interval is completed. 7

Assuming that switch 142 is closed, the second and third operations of relay 114, in response to the intermittentapplication of ringing current to the-subscribers line, close the circuit of magnet 123, and advance brush "121 to its ninth terminal. When ringing current is applied for the fourth time, the circuit controlled by relay 114 is extended over the ninth'termina'l of brush 121,.inner lower front contact ofrelay 117 winding of relay 119 to'battery. Relay. 119 operates, closing a locking circuit for itself over. its lowercontactthrough the winding of relay 118, to ground atthe. outer lower. contact of relay 117 Relay 118 cannot operate at once being shunted by ground over the contact of relay 114. Relay 119 also connects resistance 130 over its front contact and the upper back contacts of'relay 118 to the tip and ring terminals of the called subscribers line, com pleting adirect current circuit for relay 110 which operates and, in the well known manner, brings about the disconnection of the ringing current source 112. When relay 114 releases atthete'rmination of the. ringing impulses, relay118 operates and disconnects the terminalsof the subscribers line from resistancel-30, connecting them through to the tip and ringof the jack 131 located at the operators position. Itf also closes a circuit from ground over its middle lower front contact, back contact of relay 133, to lamp 132? and battery,llighting the ilamplasa signal to the operator;

The operator responds to this signal by inserting. the plug of one of her cordsinxjack 131 and operating her'listening'rkey'. Battery connected to thesleeve of the plug is extended over the sleeve of jack 131, normal contact ofrelay 133, outer lower front .con-.

tact of relay 118 to the upper winding of relay "133 and groundf Belay 133 locks over its upper alternate'contact to the sleeve of jack 131, extinguishes lamp 132 and closes a second locking circuit for itselfover its lower winding and lower front contact to ground at the-middle lower contact of relay118. -T-hefoperator may now converse with the calling subscriber, deliver any prearranged message, or takethe number and messa-geof the-calling subscriber. When the operator removes her cord'from the jack, one locking circui't'of relay 132 is opened but-that'relay remains operated luntilthe calling subscriber disconnects and the train of switches isreleased resulting in removal of battery from 133 prevents the relighting of 1211119132 after the call has been answered by the operator.

When relay 133 wasoperated it also closed a'circuit from ground over the-inner lower front contact of relay 118, outer upper front contact of'relay 133, winding of relay 134 to battery. Relay 134 looks over its inner right contact to ground at the left back contact of relay 138. v Relay 134 sets up a'condition whereby the initiation of a call on line 105 will bring about the connection of. that line with the operators position. To this end relay'134 prepares a circuit from the tip side of the subscribers line, outer upper back contact of relay 118, back contact of relay 119, left back contact of relay 135, outer left front contact of relay 134 to ground, and from the ring side of the line overthe inner upper back contact of'relay 118, inner left front contact of relay 134,right back contact of relay 135, winding of relay 136 to battery. It also prepares a circuit from ground through the winding of relay 138, outer right contact of relay 134, lower back contact of relay 118,'normal contact of relay 133 to the sleeve of jack 131. With relay 134 operated, the" shunt around relay 135 is opened and'this relay is connected between the sleeve terminal of the line at the final,

indicated for relay 136, but'relay'134 remains locked, and as soon as the incoming call has been cared for the circuit condition just described is restored. 1 Otherwise the operationin connection with an incoming call is the same as above described.

hen the subscriber at substation initiates a call, connecting his transmitter and dial across the tip and ring conductors to form a direct current path, relay 136 operates and connects battery through resistance 139 to the line finder sleeve terminals operating relay 140 and cutting off the line relay 141. It also closes a circuit from ground through interrupter 137 over the lower back contact of relay 133 to lamp 132 to cause the lamp to flash. The operator may now insert her plug in jack 131 completing the circuit of relay 138 which opens the locking circuit of relay 134, closes a substitute holding circuit for itself under the control of theoperator, closes a substitute holding circuit for the cut-ofi relay 140'and connects the talking conductors through to the jack 131. The release of relay 134 opens the circuit of relay 136 which eX- tinguishes lamp 132. The operator may deliver any messages which she has received for the subscriber and then remove her plug from jack 131. Relay 140 is then released and relay 141' can operate {so that the call initiatedby the subscriber can proceed. In case unanswered calls, are tobee'xtended to the operator only during certain periods, the circuit may be disabled at other times-by operatingkey 1 16. This prevents the operation of rela .114 from causing 'the operation of relay 11- andthereby-prevents the initiation of the cycle of operations above described.

If at any time during the operation ofthe timing switch the subscriber at substa- 1 nal of the-final selector as long as the line re- 1 mains busy at that point andholds thecutfofi relay operated to mark the'linefin'der terminals busy. When the conversation has been completed and final selector 104 releases,

relay 117 also releases closing a circuit from 9 ground over its lower back'contact to the strapped terminals of brush 122 and thence over the back 'contact and winding of magnet i 123 to battery, stepping the timing switch back to normal; If a calling subscriber abandons acall beforethe timing. switch has completed its operation, the disconnection of the final selector releases relay117 and closes the restoring circuit for. switch 120.

What is claimed is: Y l V 1. In a telephone system, a calling line,-a called line, means to establish a connection from saidgcalling line to the terminalsof W said called line,--means.to apply ringing current to said called line at definite intervalsa stepping switch,"a signal, means efi'ective in a particular position. of said stepping switch to operate. said signal, means responsive toeach application 0]": ringing current to. advance said sWitch'one st wh b .110

said'signal willbeoperated after a predetermined elapsedtimeyother means for ad vancing said" switch, and means to render said other means effective to 5 vary said elapsedtimell 2; In a telephonesystem, a calling line, a called line, means to establish a connection from saidcalling line to the terminals of said called'line, means toiapply ringing current to said called line atdefinite intervals,

a stepping switch individual to said line, a

signal, means effective in a particular posi- 1 tlon'of said-stepping switch to operate said signal, means responsive to each application of ringing current to advance said'switch one step, whereby sa d slgnal will be oper .ated after a predetermined elapsed time,

other means for advancing saidswitch', and,

means to render said other me ns effective to vary. sa1d elapsedtime. i I I I .3. In a telephone system, acal-ling' line, a telephone exchange, a called line at said exchange, an operators positionv at said ex-' change, a signalat said position, means to. establish a connection from said calling-line to the terminalsof said called line, means r line, means to establish a connection to said line, means to apply ringing current to said line, means responsive to said ringing currentto measure a time interval, means effective if the subscriber on said line fails to respond before the expiration. ofsaid interval to-extend said connection to an op'eratorZs position, and means operated in response to said extension to render the subsequent initiation of a call on said lineeiiective to connect said'line with said operators position. 5. In a telephone system,; a subscribers line,; means to establish la connection with said line, an operators positiommeans e'fi'ec- 'tive if the subscriber" on said line fails to answer before the'exp'iration of a predetermined length of time to extend said connection to said operators position, and means operative in response to said extensi'on'to render the subsequent initiation of .a call on said line effective to connect said line with said operators position I 1 6. In a telephone system, a subscribers line,pmeans to establish a connection with line, an operators;position, means effective if the subscriber on said line fails to answer before the expiration-of a predetermined length oftime to extend said connection to said operators position, a relay operated in response to said extension, means under the control of said relay to :render the-initiation of a callon said line eiiective to connect said line with said operators position, and means operated in response to theextension of other calls to said line to render the control of said relay ineiiectivei I 9. In a telephone system, a 'subscribers line, means to establish a connection with said line, an operators position, means effectiveif the subscriber onsaid line fails to answer "before the expiration of a'predetermined length of time to extend said connection to said operators position, a relay operated in responseto-said extension, means under the control'of said relay to render the initiation of a .call 'on'said line effective to connect said line with said operators posi tion, and means. operated in response to the extension of other. calls to said line to tem porarily render the control of saidrelay insaid line, an operators position, means effective if the subscriber-on said line fails to-answer before theaexpiration of: a pre determined length of time toextend said connection to. said operatorsposition, and means operative in response to said extension to render the initiation of'a call on said line efiective to connect said line withasaid operator s position andto displaya distinctive signal'at said position. .7 v

7. In a telephone system, a subscribers line, means toestablish a connection with said line, an operators position, means effective if thesubscriber on said line-tails to answer before the expiration of a predetermined length of time to extendsaid connection to said operators position, a. relay ,operated'in responsejto said extension and means under the control of said relay to r'enderthe initiation ofa callon said line effective to connectv said line with said operators position.

.8. In a telephone system, ,raasubscribers line, means to establish a; connection with said 

